Mosses (Musci), a large family of cryptoga-mic plants, the study of which forms a distinct department of botany called bryology (Gr. , moss), or muscology. Mosses have distinct stems, leaves, flower-like reproductive organs, and seed-like bodies or spores which serve to propagate the species. They are cellular, and bear only a faint resemblance to the higher orders of plants. The stem of the mosses consists of cells of different forms and sizes, as may be readily seen by a transverse section, where those of the circumference are smaller and polyhedral, while those of the centre are elongated and by a closer arrangement approximate a woody texture. The stem, when it rises upward and ends in the organs of reproduction, is said to be determinate, and such a moss is acrocarpous; but when it extends lengthwise and laterally in an indefinite manner, it is said to be indeterminate, and the moss is pleurocarpous, because the reproductive organs are borne upon the side branches. The leaves of mosses are always sessile, and usually clothe the stem; but in some species the lower part is bare, or at least only covered with a few leaf-like scales.
There are two distinct kinds of leaves: 1, those which grow upon the stem, and are called cauline; 2, those which surround the reproductive organs, and are called pericha3tial when they surround the fertile organs, and perigonial when around the male. These latter are more closely set than are the others, forming a sort of rosette in the centre of which the reproductive organs are lodged. The leaves of mosses are very simple, and usually consist of a single cellular layer, and they are destitute of stomata. They easily imbibe moisture, and as suddenly wither. A passing shower will revive the mosses which grow upon the driest rocks. The cells of the leaves are comparatively large, but the size differs greatly in different species. Each cell usually contains chlorophyl, though the cells of the sphagnum appear to be destitute of this principle. The cells are often uniform in size and general shape, except those toward the central portion of the leaf, where they assume an elongated form and constitute themselves into a sort of rib, nerve, or vein, which either bifurcates at the base and shortly ceases, or is produced into a single nerve and continues through the greater length of the leaf, or even extends beyond the apex and ends in a sort of point.
The cells upon the edges of the leaf are sometimes modified into a border or into serrated processes like teeth. Sometimes several laminae are produced along the midrib or nerve of the leaf, and sometimes granules or bulimies are produced there. Buds or innovations are also sometimes to be met with in the axils, which when separated can become new plants. With regard to the stem, the phvllo-taxis or position of the leaves is one-two, two-five or three-eight. - The floral or reproduc-tive organs arc of two kinds: 1. What may be regarded as the sterile or male flowers, the antheridia, consisting of cylindrical, pear-shaped, or ellipsoidal stalked sacs containing a granular mocilage, which when the antheri-Him is mature is expelled from an opening in uio apex; it consists of spherical hyaline cells from 1/2600 to 1/3500 of of an inch in diameter, each containing a filiform antherozoid, which is furnished with two minutely slender, vibrating hairs. The antheridia are accompanied by cellular jointed filaments called paraphyses. 2. The archegonia, which may be compared to fertile or pistillate flowers, are usually flask-shaped bodies, mixed, like the antheridia, with paraphyses, and like them produced within small clusters or rosettes of leaves.
The cavity of the archegonium contains a free cell or nucleus, enveloped by mucilage; after fertilization the archegonium elongates, as does its enclosed nucleus; but the nucleus grows much more rapidly than the archegonium, which at length is ruptured, its upper part forming a cap, called the calyptra; the nucleus in elongating forms a slender bristle, still capped by the calyptra, and when it has attained its full length the portion within the calyptra expands, and forms a capsule (theca, or urn), which is known as the fruit of the moss. The lower portion of the ruptured archegonium remains at the base of the bristle as a vaginula or sheath. In general, a single archegonium only becomes perfect and undergoes these changes. These two distinct kinds of floral organs sometimes exist in the same flower and are enclosed in the same perichaetium, when the moss is called syncecious; if, however, the antheridia occur on one part of the plant and the arche-gonia on another part, the moss is called monoecious; and when each kind of organ occurs on separate plants, the moss is dioecious.
The importance of these differences in the mosses is apparent from the fact that some species produce in some countries only barren flowers or antheridia, and consequently can never be found there in fruit, a condition always desirable to those who collect for herbariums. It has been well ascertained that where the antheridia are wanting the archegonia never come to perfection; and there are some dioecious species of hypnum, for instance, which are usually destitute of capsules from that cause. - The capsule, sporangium, or theca of mosses is cellular, has a central axis called the columella, and contains spores. In some instances the sporangium is indehiscent (e. g., phascum); in other cases it opens by four lateral valves (android), but in the majority of mosses it opens by means of a lid (operculum). This lid is thrown off when the sporangium is mature. Between the base of the lid and the edge of the mouth of the capsule or sporangium are frequently several rows of large cells forming a sort of ring (annulus), which distend themselves and assist in the dispersion of the spores. The edge of the mouth of the capsule in some mosses is entire (e. g., gymnostomum), or it has a fringe (peristome) consisting of prolongations and divisions of the two inner parietal layers of the capsule.
The peristome consists of one or more rows of hygrometric cellular teeth, which are four or some multiple of that number. Where but a single row exists, the mosses are classed as aploperistomi, and where there are double rows as diploperistomi. The teeth are long and twisted together in baroula, or bifurcate in dicranum, or assume a variety of shapes, marking the different genera. In some mosses the inner parietal layer appears as a membrane called the epiphragm or tympanum, stretched across the mouth from the walls of the sporangium to the columella. The capsule does not always rest in a perpendicular manner upon the seta, but may be inclined to one side, and bent downward or cernuous; and in some mosses one side of it is more developed than the other, producing an unsym-metrical shape. Sometimes there is a considerable thickening or swelling at its base, to which the name of apophysis is given. The interior of the mature capsule is tilled with a profusion of dust, which however will be found to consist of round bodies, which are in fact the spores or seeds. When they have been ejected from the capsule, they are in a condition to grow.
From some part of their surface a bladder-like swelling protrudes, which after a while extends itself by increase of similar ones into a confervoid thread. An entangled mass of such threads soon covers the soil, or the moist surfaces of substances on which the spores have fallen. So much do these threads resemble some of the algse, that they were mistaken for them by the earlier botanists. This confervoid vegetation continues from 5 to 20 days, when upon its surface very small buds appear. On examination these buds will be found to be composed of minute scaly leaves; and thus the axis or future stem is originated at their base. In some genera the moss scarcely develops itself beyond this condition, forming its fruit in the interior of the scale-like foliage. In other kinds of mosses the plants grow for a shorter or longer period of time before the inflorescence appears. These confervoid threads have been compared to the primordial leaves of the higher orders of plants; they differ however in this, that on disappearing from the surface of the soil, similar threads penetrate it and seem to careless observers to be the roots.
In many mosses such seeming roots are pushed from the under side of the stem, or even from the very extremities, in the progress of its growth. - Very little is known of the uses of the mosses. In the economy of nature they serve as precursors of the higher plants, appearing first upon sterile places, and collecting among their matted and tufted stems the dust and sand. They afford secure lodging places for insects in winter, as well as food for them in summer. Some species of sphagnum enter largely into the formation of peat bogs; in these localities the moss continues to grow above while it is constantly decaying below; a great number of woody plants are found growing with the sphagnum, and these decaying together with the moss form peat of various qualities. Some botanists regard sphagnum as sufficiently different from other mosses to form an order by itself (sphagna), intermediate between the true mosses and the liverworts. When first taken from the bog sphagnum is very wet, but if thoroughly squeezed or partly dried it serves an excellent purpose in the transmission of trees and plants by packing their roots in the spongy and elastic mass; indeed for this purpose it is superior to all other packing materials; it may be made to contain just the requisite amount of moisture, and it does not readily decay.
It is also much employed by gardeners as a medium in which to grow orchids and plants that are naturally inhabitants of bogs, and for these uses it is a regular article of trade. Some hypna retain their elasticity on being dried, and serve for stuffing pillows. The Laplanders use turfs of polytrichia for mattresses. Little brooms are sometimes made of these mosses. In dense forests (in the northern hemisphere) the northern side of trees is usually more thickly covered with mosses than the other sides. Some fanciful medicinal qualities are attributed to a few kinds. - The geographical distribution of the mosses is very extensive; scarcely any part of the earth's surface is destitute of them, from the polar regions to the equator. They constitute with lichens almost the only vegetation on the coast of the Polar sea, where the soil never thaws to a depth of more than a few inches. The northern seacoast of Siberia is an immense morass whose entire surface is covered with mosses. The schistose rocks of Spitzbergen, rising above the everlasting ice, are, according to Martens, covered with these plants. They enter largely into the flora of Greenland; the loftiest Swiss Alps, and the volcanic scoria) of Iceland, afford abundant species.
Montagne in his Sylloge exhibits species from almost every portion of the globe, and the various exploring expeditions find these forms of vegetation wherever they have visited. - The earliest writer on the mosses who comprehended their structure was Micheli, who in 1720 described and depicted the most minute portions of their reproductive organs, and seems to have understood their purp - 9. On the other hand, Dillenius (1741), Linnaeus (1753), and Adanson (1763) regarded the sporangium as analogous to the anther of the phanogamous plants. Schmiedel in 1760, and subsequently in his Icones Plantarum et Analyses Partium (1702-'97), described and figured the zoothecae of the hepaticce; and, struck with finding them tilled with a mucilaginous fluid analogous to that which fills the pollen grains, he considered them as male organs, and gave the name of female organs to the sporangia of mosses, Hedwig (Theoria Generationis, 1784) and other botanists now adopted the same view, until II. Mold in 1833 showed that the spores of the hepatic® and mosses were developed exactly like the pollen grams, and that the ideas of Linnanis and others of that school were in a measure correct We have seen, however, that the antheridia with their enclosed antherozoids seem to be essential in the production of the sporangium and its contents.
In the United States the mosses were perhaps first collected by Dr. Muhlenberg, of Lancaster, Pa. He sent many American species to Hedwig, and they were described and published in the Species Muscorum (Leip-sic, 1801). In 1813 Muhlenberg's Gatalogus Plantarum America Septentrionalis appeared, in which he gives the names of more than 170 species. The value of this list is apparent, when it is known that his correspondence abroad was extensive and highly prized. Many of the species in Bridel's Bryologia Universa (Leipsic, 1826) were from contributions of Dr. Torrey of New York, who at that time had made ample collections of cryptogamic plants; and mention is frequently made by the same author of the names of Oooley and Dewey, who likewise furnished specimens. Those of Newfoundland had been collected by De la Pylaie. A synoptical table of the ferns and mosses of the United States was published in 1828 in the "American Journal of Science and Arts," vol. xv., by Dr. Lewis C. Beck. A list of the mosses of Massachusetts is appended to the second edition of Prof. Hitchcock's "Geological Report" of that state.
The mosses of the British possessions in North America were collected by Drummond, the author of Mnsci Scotici, who accompanied Franklin in his second land expedition in 1825. These subsequently appeared in sets of mounted specimens published by William Wilson at Glasgow in 1828; they were choice and valuable. In the Boston " Journal of Natural History " for 1845 (vol. v.) is a paper by John L. Russell on some species noticed by him in eastern Massachusetts; and in Hovey's "Magazine of Horticulture and Botany" for 1847, vol. xiii., is a valuable list of White mountain species prepared by William Oakes, who had made that region of New England his special study. In the catalogue of the plants of Cincinnati, Ohio, by Thomas G. Lea, are more than 80 species collected by him. In Agassiz's "Lake Superior, its Physical Character, Vegetation," etc. (Boston, 1850), the mosses of that region are elaborated- by Les-quereux. Dr. Darlington, in the second edition of his Flora Cestrica (Philadelphia, 1853), furnishes a list of species detected within the limits of Chester co., Pa., and prepared by Thomas P. James. The Mnsci Alleghanienses were issued from Columbus, O., in 1855, in two fascicles (4to), consisting of 215 species and well marked varieties of mosses, and 177 species of hepatice.
Fifty copies only of this superb work were printed for private distribution among the friends of the author. These specimens were collected by William S. Sullivant and Prof. Asa Gray, in a tour along the Alleghany mountains from Maryland to Georgia in 1853. A similar work from the joint studies of Lesquereux and Sullivant, consisting of 355 mounted specimens, and entitled Musci Bo-reali-Americani (Columbus, O., 1856), full of rich and well fruited species, and thus giving a view of the muscology of North America, furnishes ample materials for comparison. In the second edition of Prof. Asa Gray's "Manual of the Botany of the Northern United States" (1856) Mr. Sullivant gave descriptions of all the species known eastward of the Mississippi river; but in subsequent editions of the "Manual" these are omitted, and they have been published in a separate volume as " The Musci and Hepaticae of the United States east of the Mississippi River." A most important aid to the student is "The Icones Muscorum, or Figures and Descriptions of most of those Mosses peculiar to Eastern North America which have not heretofore been figured." This, also by Mr. Sullivant, is a handsome volume, with 129 copperplates, each illustrating several species.
A description of the mosses and liverworts found on the United States Pacific railroad expeditions and surveys, with figures of the rarer and new species by Mr. Sullivant, can be found in the fourth volume of the executive documents (senate) of the 33d congress, second session (Washington, 1856). Other valuable contributions in this branch of botany from the same pen are to be seen in the " Memoirs of the American Academy of Arts and Sciences" (Boston, 1848, &c). The species found in Wisconsin are given by I. A. Lap-ham, in the fifth volume of the "Transactions of the Wisconsin State Agricultural Society " (1860). Many novelties likewise have been brought to notice through the labors of C. 0. Frost of Brattleboro, Vt., and by Prof. D. C. Eaton of New Haven, who have minutely examined that region. Mr. C. F. Austin, of Closter, N. J., has published named collections of mosses. The "Bulletin of the Torrey Botanical Club " (monthly, New York) contains important contributions to our bryology by Mr. Austin, and, especially with reference to southern and far western species, by Dr. Carl Mtiller of Halle, Germany.
Sterile Inflorescence. 1. A sterile Stem. 2. Antheridia (one emitting antherozoids) and Paraphyses. 3. An-therozoids.
Fertile Inflorescence. 1. A fertile Stem. 2. Capsule with its Calyptra. 3. Capsule deprived of Calyptra, showing the Operculum. 4. The same with Operculum removed, exposing the Peristomium and Epiphragm.
Pcat Moss (Sphagnum acatifolium).